Electromagnetic structure



May 9 1957 v F. E. MYERS '3,319,196

ELECTROMAGNETI C STRUCTURE Filed Oct. 15, 1965 3 Sheets-Sheet l May 9, 1967 F.1E. MYERSv 3,319,196

ELECTROMAGNETI C STRUCTURE Filed Oct. 13, 1965 5 Sheets-Sheet 2 May 9, 1967. F. E.. MYER'l l 3,319,196',

ELECTROMAGNETIC STRUCTURE I Filed oct. 13,1965 5 sheets-Sheet s United States Patent O 3,319,196 ELECTRQll/IAGNETIC STRUCTURE Felix E. Myers, Haddon Heights, NJ., assgnor to I-T-E Circuit llireaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Oct. 13, 1965, Ser. No. 495,526 12 Claims. (Cl. 335-38) My invention relates `to electromagnetic structures in general, and- -more particularly to `a unitary magnet and cooperating armature assembly, of extreme compactness, simplicity of operation and ease of fa'brication.

Electromagnetic structures as presently available include a diverse arrangement of cooperating magnet and armature configurations. In the past, such electromagnetic actuating structures have typically included a multiplicity of individual members which are separately inserted within the housing of the device carrying same. In some applications it is extremely desirable that the armature and magnet be assembled as a low-cost unitary assembly for simple insertion in its switching device. As, for example, the shunt-trip device disclosed in copending U.S. patent application Ser. No. 487,016 in the name of Carl E. Gryctko, entitled, Circuit Breaker Stack Including Auxiliary Features, tiled Sept. 13, 1965, and assigned to the assignee of the instant invention, is an extremely compact device. Only a minimum volume is provide-d for the reception of the entire electromagnetic actuating means, including U-shaped magnet structure, armature, and bobbin coil assembly. For ease of fabrication, and initial calibration, it is extremely desirable that the entire actuating unit for insertion in such a device be previously fabricated as a unitary assembly for insertion Within the housing of the shunt-trip device.

Basically, my invention aptly satisfies these requirements by providing a novel ybobbin assembly which carries both the coopera-ting magnet and armature means. More specically, the bobbin assembly includes an axially extending hollowed core and transversely extending side walls at the opposed axial ends thereof. The magnet is in the general form of a U, with the body portion thereof passing through the bobbin core and the arms thereof transversely extending along the bobbin side walls to forml pole faces at their free ends. The sidel walls further include armature mounting means which receive, and pivotally mount the armature, to dene a V-shaped air gap intermediate the armature and the pole faces of the U-shaped magnet. A biasing means, in the form of a spring, extends intermediate the armature and another region of the bobbin side Walls so as to 'bias the armature away from the cooperating magnet pole faces. The energizing coil is wound about the bobbin` core intermediate the bobbin side walls, such that a ux path will `be generated through the U of the magnet, across the V-shaped air gap and to the armature means. Upon actuation of the energizing coi-l the armature moves towards the cooperating pole faces, against the biasing effect of the spring. Advantageously, the side walls also include locating means, which are positioned to register with cooperating housing means such that the entire electromagnetic assembly may be dropped within the housing and will be retained within a desired region of its said housing.

The bobbin assembly also includes external terminal connections, circuit-connected to the opposed end windings of the `energizing coil which permit their connection to the external energizing circuit. According to another advantageous aspect of my invention, these terminal connections are made to elements of the shunt-trip device connectab-le to the external circuit prior to its insertion within the unit housing. This avoids the need to solderconn-ect at relatively inaccessible and inconvenient locations.

It is, therefore, seen that a principal object of my invention resides in providing an electromagnetic structure of improved compactness, simplicity of operation and ease of fabrication.

A further object of my invention is to provide a unitary electromagnetic structure wherein the magnet, armature means and supporting structure are all formed as a subassem-bly unit.

Another object of my invention is to provide an electromagnetic structure of the unitary type, wherein a U- shaped magnet is formed about a hollowed bobbin assembly, with the armature being operatively mounted to the bobbin assembly together with cooperating biasing means and energizing means.

An additional object of my invention is to provide an extremely compact electromagnetic structure which may 'be conveniently inserted within the relatively small volume of a circuit breaker shunt-trip device.

These as well as other objects of my invention will become readily apparent upon a consideration of the following descriptions and drawings in which:

FIGURE 1 is a cross-sectional View of a circuit breaker auxiliary trip device, shown in the non-actuated condition and utilizing an electromagnetic structure in accordance with one form of my invention.

FIGURE 2 is a cross-sectional view, corresponding to FIGURE 1, ybut showing the unit in the actuated condition.

FIGURE 3 is an exploded perspective view of the particular form of electromagnetic structure constructed in accordance with my invention, as utilized in the device of FIGURES l and 2.

FIGURES 4, 5 and 6 are side elevation, plan and end views, respectively, of the bobbin member used in the assembly of the instant electromagnetic tripl structure.

FIGURES 7 and 8 are side elevation and end views, respectively, corresponding to FIGURES 4 and 6 above, but showing the addition of the U-shaped magnet means and energizing coil.

FIGURE 9 is a side elevation View of the completely fabricated electromagnetic trip structure, together with associated elements of shunt-trip device which are electrically connected to the externa-l circuit.

FIGURE l0 is an exploded perspective view of another form of my invention, utilizing a slightly moditied assembly of the U-shaped magnet means.

Referring initially to FIGURES 1 and 2, assembly 10 is a circuit breaker shunt-trip device of the type which is the subject of aforementioned U.S. patent application Ser. No. 487,016, and is shown with an electromagnetic actuating structure 5d, in accordance with the one form of the instant invention. It should, however, be understood that this particular application of my invention is for i1- lustrative purposes only, and the broad concepts thereof may be practiced in conjunction with numerous other electromagnetic structures and associated mechanisms.

Shunt trip unit 10 comprises a base 18 of molded insulated material having an open side, capped by a removable cover (not shown), which is also constructed of a similar molded insulating material. The cover is secured to base 18 by a number of spaced rivets 21. Molded base member 18 and its cooperating cover include a plurality of pockets which are suitably located for receiving and maintaining the various operating components thereof, including the electromagnetic structure 50 of the instant invention, as will be henceforth described.

A stationary contract member 22 is mounted to the conductive member 23 which is, in turn, connected to external circuit connector 24. Cooperating with stationary contact 22 is movable contact 26 which is mounted to the lower end of movable contact arm 27. The upper end of the contact arm 27 abuts a suitable pivot-forming formation of manual operating member 28. Manual operating member 28 is pivoted about protrusions 29 thereof which are entered into suitable recesses (not shown) of the molded base 18 and cooperating cover member. Manual operating member 28 includes the portion 16 extending outward of molded base 18 which serves as the manual operating handle in the well known conventional manner.

Operating mechanism 30 for bringing about the eng-agement and disengagement of cooperating contacts 22-26 comprises latchable cradle 31 which is pivoted at one end thereof at base protrusions 32. One end of an operating spring 33 is connected to cradle 31 at a point intermediate the end thereof, while the other end of spring 33 is tied to an intermediate region of contact arm 27. Operating spring 33 is tensioned, thereby urging contact arm 27 upward into engagement with its pivot on manual operating member 28. The other end of cradle 31 comprises a latch tip 34 which is engageable by latch 35 secured to elongated member 36.

A conducting braid 40 extends from contact arm 27 to a terminal 102 of the electromagnetic structure 50, which is connected to end 104 of energizing coil means 106. 'The opposite coil end 108 is connected to terminal 110, carried by the electromagnetic structure 100, which is, in turn, connected by braid 137 to external terminal member 58. Elongated latch-carrying member 36 is biased in a clockwise direction by spring 40 disposed in recess 40 of base 18, with one end of spring 40" abutting wall 42 of recess 40" and the other end of spring 40' abutting the portion of elongated latch-carrying member 36 positioned above its pivot 37.

Reference is now made to FIG'URES 3 through 9 to show in further detail the construction of the electromagnetic structure 50 which encompasses the subject matter nf the instant invention. A bobbin 112 is provided which includes core portion 114 extending in the direction of axis115 and side walls 116, 118 at the opposed axial ends thereof. Bobbin member 112 is formed of a suitable insulated material, such as, for example, molded Lexan or molded nylon.

Upper and lower locating protrusions 120, 122 outwardly extend from the respective side walls 116, 118, and are positioned to conveniently enter molded housing recesses 121, 123 at one end, and similarly aligned cover recesses (not shown) at its opposite axial end for maintaining the bobbin member 112 in a desired region of the molded housing 18. Core section 114 of bobbin 112 includes a hollowed opening 130 of a suitable conguration to receive body portion 132 of the magnet means. Magnet arm members 134, 136 transversely extend from the opposed axial ends of body portion 132, along the side walls 116, 118, respectively, of the bobbin. Reduced cross-sectional ends 133, 133 of the magnet body portion enter openings 137, 139, respectively, of the magnet side pieces and are securably staked thereto so as to form such a U-shaped magnet structure about the bobbin 112. Coil 106 is wound about core 114, with the ends 104, 108 of coil 106 being connected to terminal means 102, 110 which are carried by opposed side walls 116, 118 of the bobbin assembly. A notched region 135 is formed at the lower end of the side walls 116, 118, respectively, for pivotally receiving armature member 125. Adjacent this notched region are a pair of aligned openings 136, 138 in the bobbin side walls which pivotally receive axially extending armature portions 140, 142 for mounting armature member 125 to the bobbin assembly 112. It is to be noted that a Vgenerally V-shaped air gap is formed intermediate the pole faces 115 at the ends of U-shaped arms 135, 136, respectively, and armature member 125. Armature member 125 is biased away from the cooperating pole faces by a leaf spring member 150 having one end 152 thereof secured to the armature, adjacent the apex end of the V gap, and the opposite end 154 thereof abutting region 155 of the bobbin. This mounting of the armature to unitary bobbin advantageously provides suitable compensation for over-travel of the tripping members. It is to be noted that in the non-actuated condition, surface 157 of the bobbin, adjacent notch 135, serves as a stop to limit the biased movement of the armature away from the cooperating pole faces 115.

The armature 12S includes an operating portion 160 which generally spans the axial space between the pole faces of the U, and is positioned for movement towards and away from such Ipole face corresponding to the actuation of coil 106. Extending trip portion 162 has an end 127, which will engage latch tip extension 39 during movement of the armature 125 towards the pole faces 115 so as to bring about the unlatching of cradle latch tip 34 and latch 35.

The normal position of elongated member 36 is ad- Ijusted by screw 43 which extends through an opening rin base 18. Screw 43 abuts tensioning member 46, and as it is turned, forces tensioning member 46 against elongated member 36 so as to move that member about its pivot 37 for adjusting the engagement of the cradle latch tip 34 with the l-atch 35 and the separation between latch end tripping extension 39 and extension 127 of armature member 125. The tripping of shunt-trip device 10 is achieved by energization of electromagnetic actuating coil 106. When coil 106 is energized, the flux path flowing through the magnet members thereof, and particularly the flux linkage between magnet pole faces and armature urges the armature member 125 about its pivot 136, thereby closing the V-shaped separation therebetween. This will effect counter-clockwise movement of elongated member 36 about its pivot 37, as determined by the abutting engagement of armature end extension 127 and latch extension 39, such that cradle tip 34 will be released from latching engagement with latch tip 35, thereby effecting movement of the operating mechanism to the actuated condition shown in FIGURE 2. A roller 59 is also mounted to cradle 31 at 59, such that as the cradle tip 34 is unlatched from 35, cradle 31 will move in a direction bringing about striking engagement of roller 59 against trip member 61 so as to rotate the latter member counter-clockwise about its pivot 37. As is fully discussed in aforementioned copending U.S. patent application Ser. No. 487,016, the unlatching of cradle member 31 is transmitted to a plurality of adjacently stacked devices (not shown) closely corresponding to the construction of unit 10. This is achieved by interconnecting elongated control member 1-7 which is located within a rectangular opening 53 of trip members 61 of such adjacently stacked devices. Hence, the counter-clockwise movement of trip member 61 will be transmitted to the similar trip members of the adjacently stacked units. Typically, such adjacently stacked units may be conventional circuit breaker devices of the type shown in my U.S. Patent No. 2,996,589, entitled Pivoted Bimetal, issued Aug. 15, 1961, and also assigned to the assignee of the instant invention. The elongated member (corresponding to member 36 vof shunt-trip device 10) ofV such similar circuit breaker devices is typically of the bimetallic variety which,

.when heated a prcdeterminedly calibrated amount, will deect to bring about unlatching of a latch tip of a cradle 31 similar to that shown in the instant shunt-trip device. Conversely, actuation of the instant shunt-trip device will be transmitted to such adjacently stacked devices (via elongated member 17 and the trip members ofthe device) such that the adjacently stacked circuit breaker units will be tripped open upon actuation of the shunt-trip unit 10.

Referring to FIGURE 9, the entire sub-assembly of the electromagnetic trip structure, prior to insertion within the switch device housing, is shown in accordance with a particularly advantageous form of my invention. Specifically, braid 137 connected to one of the external terminals 58, as well as braid '40 connected to mov-able contact arm 27, is welded to the electromagnetic sub-assembly terminals 102, 110 as a unitary sub-assembly. Hence, the entire unit, as shown in FIGURE 9, is inserted within the housing, thereby avoiding the need for any further soldering, welding, or other tedious electrical connections to be made in the rather confined quarters of the switch device housing.

Reference is now made to FIGURE l which shows a slightly modified form of my invention, and wherein components corresponding to that shown in the above discussed embodiment are designated by the same numerals. More specifically, the U-shaped magnetic structure of body member 132 and side -arms 134, 136, as shown in the previously discussed embodiment, has been replaced with a dual L-shaped construction, as is the subject of U.S. patent application Ser. No. 486,815, entitled, Electromagnetic Structure, filed Sept. 13, 1965, in the name of Charles T. Robins and Weston W. Goodnow, and assigned to the assignee of the instant invention. Namely, this construction avoids the staking of the body member to the side members. The L-shaped members 170, 172 of the embodiment shown in FIGURE are placed through the opposite axial ends of core opening 130 such that the body portions 171, 173 .thereof are in juxtaposed adjacent planar reltationship and the arm portions 174, 176 outwardly extend therefrom to define a generally U-shaped configuration having pole faces 175 at the free ends thereof. The core opening 130 is of a suitable configuration to snugly receive body sections 171, 173. When `the bobbin coil 106 is energized, the magnetic fiux passing through the joint of body sections 171, 1.73 will pull these respective members closely together, in intimate contact, thereby automatically eliminating any small spacing therebetween that might tend to increase the reluctance of the joint. Thus, this structure advantageously provides a compact, reliable electromagnetic trip unit, which does not require the utilization of screws, stakes, rivets or simila-r fastening means for the assembly thereof.

It should further be understood that the inventive concepts of the instant invention may likewise Ybe practiced in conjunction with numerous other electromagnetic trip structures, and associated switching devices, without departing from the spirit and scope of the invention. Hence, although there have been described preferred embodiments of this novel invention, many variations and modications thereof will now be apparent to those skilled in the art, and the invention is to be limited not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows.

1. An electromagnetic structure comprising a bobbin, and cooperating magnet and armature means carried by said bobbin as a unitary assembly, said bobbin having an axially extending core, and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm lmeans at the opposed ends thereof, said first and second arm means transversely extending along said first and second sidewalls respectively to deiine a generally U-shaped magnetic structure about said bobbin, the free ends of said first and second arm means lying within a common pl-ane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from said pole faces, and a second position, in flux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting movement thereof between said first and second positions co1'- responding to actuation of said energizing coil.

2. An electromagnetic structure as set forth in claim 1, wherein said mounting means including aligned aperture means, in said first and second sidewalls, said armature means including an operating portion for movement towards and away from said pole faces, between said first and second positions, and a mounting portion, axially extending into said aperture means for mounting armature means to the sidewalls of said bobbin.

3. An electromagnetic structure comprising a bobbin and cooperating magnet and armature means carried by said bobbin as a unitary assembly, said bobbin having an axially extending core and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends thereof, said first and second arm means transversely extending along said first and second sidewalls respectively, to define a generally U-shaped magnetic structure about said bobbin, the free ends of said first and second arm means lying within a common plane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from s-aid pole faces in a manner forming a V-shaped air-gap therebetween, and a second position, in flux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting pivotal movement thereof between said first and second positions corresponding to actuation of said energizing coil, said mounting means including aligned aperture means, in said first and second sidewalls, adjacent the vertex of said V-shaped air gap, said armature means including an operating portion for movement towards and away from said pole faces, between said lfirst and second positions, and a mounting portion, axially extending into said aperture means for pivotally mounting armature means to the sidewalls of said bobbin.

4. An electromagnetic structure as set forth in claim 1, further including biasing means, carried by said bobbin for urging said armature means towards said first position.

S. An electromagnetic structure as set forth in claim 3, further including biasing means, carried by said bobbin for urging said armature means towards said first position, said biasing means including a leaf spring, a first end of said leaf -spring secured to said armature means, adjacent the open end of the V gap, and .a second end of said leaf spring abutting a surface of said bobbin.

`6. A switching device comprising a movable switching arm, an operating mechanism for moving said switching arm between at least first and second switch conditions, said operatingfmechanism including a latchable means, and means biasing said latchable means towards a first position, latch means for maintaining said latcliable means in a second position, switch actuating means for moving said latch means in a direction t-o unlatch said latchable means, and thereby permit movement thereof to its first position, such that said switching arm moves between said first and second switch conditions, said actuating means including an electromagnetic structure, said electromagnetic structure comprising a bobbin and cooperating magnet and armature means, carried by said bobbin as a unitary assembly supported in said switching device, said bobbin having an axially extending core, and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends there-of, said first and second arm means transversely extending along said first and second sidewalls respectively, to define a generally U-shaped magnetic structure about said bobbin, the free ends of said first and second arm means lying within a common plane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from said pole faces, and a second position, in ux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting movement thereof between said first and second positions corresponding to actuation of said energizing coil.

7. A switching device comprising a movable switching arm, an operating mechanism for moving said switching arm between at least first and second switch conditions, said operating mechanism including a latchable means, and means biasing said latchable .means towards a first position, latch means for maintaining said latchable means in a second position, switch actuating7 means for moving said latch means in a direction to unlatch said latchable means, Yand thereby permit movement thereof to its first position, such that said switching arm moves between said first and second switch conditions, said actuating means including an electromagnetic structure, said electromagnetic structure comprising a bobbin and cooperating magnet and armature means carried by said bobbin as a unitary assembly supported in said switching device, said bolbbin having an axially extending core, and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends thereof, said first and second arm means transversely extending along said rst and second sidewalls respectively to define a generally U-shaped magnetic structure about said bobbin, the free ends of said first and second arm means lying within a common plane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from said pole faces in a manner forming a V-shaped air-gap therebetween, and a second position, in fiux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting pivotal movement thereof between said -first and second positions corresponding to actuation of said energizing coil, said mounting means including aligned aperture means, in said rst and second sidewalls, adjacent the vertex of said V-shaped air gap, said armature means including an operating portion for movement towards and away from said pole faces, between said first and second positions, and a mounting portion, axially extending into said aperture means for pivotally mounting armature -means to the sidewalls of said bobbin.

8. A switching device as set forth in claim 7, further including biasing means, carried by said 'bobbin for urging said armature means towards said first position, said biasing means including a leaf spring, a first end of said leaf spring secured to said armature means, adjacent the open end of the V gap, and a second end of said leaf spring abutting a surface of said bobbin.

9. A switching device comprising a housing, a movable switching arm mounted t-o said housing, an operating mechanism for moving said switching arm between at least first and second switch conditions, said operating mechanism including a latchable means, and means biasing said latchable means towards a first position, latch means for maintaining said latchable means in a second position, switch actuating means for moving said latch means in a direction to unlatch said latchable means, and thereby permit movement there-of to its `first position, such that said switching arm moves between said first 'and second switch conditions, said actuating means including an electromagnetic structure, said electromagnetic structure comprising a bobbin and cooperating magnet and armature means carried by said bobbin as a unitary assembly supported in the housing of said switching device, said bobbin having an axially extending core, and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends thereof, said first and second thereof between said first and second positions correspond-Y ing to actuation of said energizing coil, said housing means including locating recess means for receiving said actuating means, and said sidewalls including locating protrusions, positioned to register with said housing recess means, such that said actuating means is retained within a desired region of said housing.

10. A shunt trip comprising a housing, a movable switching arm mounted to said housing, an operating mechanism for moving said switching arm 'between at least first and second switch conditions, said operating mechanism including a latchable means, and means biasing said latchable means towards a first position, latch means for maintaining said latchable means in a second position, switch actuating means for moving said latch means in a direction to unlatch said latchable means, and thereby permit movement thereof to its first position, such that said switching arm moves between said rst and second switch conditions, coupling means for transmitting said switch conditions to at least one circuit breaker device, external of said shunt trip housing, such that the actuation of said shunt trip is effective to operate a circuit breaker device, said actuating 'means including an electromagnetic structure, said electromagnetic structure comprising a bobbin and cooperatnig magnet and armature means carried yby said -bobbin as a unitary assembly supported in the housing of said switching device, said bobbin having an axially extending core, and transversely extending first and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intermediate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends there` of, said first and second arm means transversely extending along said first and second sidewalls respectively t-o define a'generally U-shaped magnetic structure about said bobbin, the free ends of said first and second arm means lying within la common plane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from said pole faces, and a second position, in flux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting movement thereof between said first and second positions corresponding to actuation of said energizing coil, said housing means including locating recess means for receiving said actuating means, and said sidewalls including locating protrusions, positioned t-o register with said housing recess means, such that said actuating means is retained within a desired region of said housing.

11. A shunt trip comprising a movable switching arm, an operating mechanism for moving said switching arm between at least first and second switch conditions, said operating mechanism including a latchable means, and means biasing said latchable means towards a first position, latch means for maintaining said latchable means in a second position, switch actuating meansfor moving said latch means in a direction to unlatch said latchable means, and thereby permit movement thereof t-o its first position, such that said switching arm moves between said first and second switch conditions, coupling -means for transmitting said switch conditions to at least one circuit breaker device, external of said shunt trip housing, such that the actuation of said shunt trip is effective to operate a circuit 'breaker device, said actuating means including an electromagnetic structure, said electromagnetic structure comprising a bobbin and cooperating magnet and armature means carried by said bobbin as a unitary assembly supported in the housing of said switching device, said bobbin having an axially extending core, and transversely extending rst and second sidewalls at the opposed axial ends thereof, an energizing coil wound about said core and axially located intererndiate said sidewalls, said magnet means including a body section axially extending through said core, and first and second arm means at the opposed ends thereof, said first and second arm means transversely extending along said first and second sidewalls respectively to define a generally U-shaped magnetic structure about said bobbin, the free ends of said first and second lar-m means lying within a common plane to define a pair of axially spaced pole faces, said armature means axially spanning said pole faces and having a first position, separated from said pole faces, in a manner forming a V-shaped air-gap therebetween, and a second position, in liux coupled engagement with said pole faces, said bobbin including mounting means for retaining said armature means and permitting pivotal movement thereof between said first and second positions corresponding to actuation of said energizing coil, said mounting means including aligned aperture means, in said rst and second sidewalls, adjacent the vertex of said V-shaped air gap, said housing means including locating recess means for receiving said actuating means, and said sidewalls including locating protrusions, positioned to register with said housing recess means, such that said actuating means is retained within a desired region of said housing.

12. A shunt trip as set forth in claim 11, further including biasing means, carried by said bobbin for urging said armature means towards said first position, said biasing means including a leaf spring, a. first end of said leaf spring secureed to said armature means, adjacent the open end of the V gap, and a second end of said leaf spring abutting a surface of said bobbin.

No references cited.

BERNARD A. GILHEANY, Primary Examiner. H. BROOME, Assistant Examiner. 

3. AN ELECTROMAGNETIC STRUCTURE COMPRISING A BOBBIN AND COOPERATING MAGNET AND ARMATURE MEANS CARRIED BY SAID BOBBIN AS A UNITARY ASSEMBLY, SAID BOBBIN HAVING AN AXIALLY EXTENDING CORE AND TRANSVERSELY EXTENDING FIRST AND SECOND SIDEWALLS AT THE OPPOSED AXIAL ENDS THEREOF, AN ENERGIZING COIL WOUND ABOUT SAID CORE AND AXIALLY LOCATED INTERMEDIATE SAID SIDEWALLS, SAID MAGNET MEANS INCLUDING A BODY SECTION AXIALLY EXTENDING THROUGH SAID CORE, AND FIRST AND SECOND ARM MEANS AT THE OPPOSED ENDS THEREOF, SAID FIRST AND SECOND ARM MEANS TRANSVERSELY EXTENDING ALONG SAID FIRST AND SECOND SIDEWALLS RESPECTIVELY, TO DEFINE A GENERALLY U-SHAPED MAGNETIC STRUCTURE ABOUT SAID BOBBIN, THE FREE ENDS OF SAID FIRST AND SECOND ARM MEANS LYING WITHIN A COMMON PLANE TO DEFINE A PAIR OF AXIALLY SPACED POLE FACES, SAID ARMATURE MEANS AXIALLY SPANNING SAID POLE FACES AND HAVING A FIRST POSITION, SEPARATED FROM SAID POLE FACES IN A MANNER FORMING A V-SHAPED AIR-GAP THEREBETWEEN, AND A SECOND POSITION, IN FLUX COUPLED ENGAGEMENT WITH SAID POLE FACES, SAID BOBBIN INCLUDING MOUNTING MEANS FOR RETAINING SAID ARMATURE MEANS AND PERMITTING PIVOTAL MOVEMENT THEREOF BETWEEN SAID FIRST AND SECOND POSITIONS CORRESPONDING TO ACTUATION OF SAID ENERGIZING COIL, SAID MOUNTING MEANS INCLUDING ALIGNED APERTURE MEANS, IN SAID FIRST AND SECOND SIDEWALLS, ADJACENT THE VERTEX OF SAID V-SHAPED AIR GAP, SAID ARMATURE MEANS INCLUDING AN OPERATING PORTION FOR MOVEMENT TOWARDS AND AWAY FROM SAID POLE FACES, BETWEEN SAID FIRST AND SECOND POSITIONS, AND A MOUNTING PORTION, AXIALLY EXTENDING INTO SAID APERTURE MEANS FOR PIVOTALLY MOUNTING ARMATURE MEANS TO THE SIDEWALLS OF SAID BOBBIN. 